Cleanable coating for projection screen

ABSTRACT

A method for providing a projection screen for receiving stereoscopic images may include providing a substrate with a contoured, reflective surface, wherein light reflected from the substrate substantially may undergo no more than a single reflection and may also include coating a first layer on the substrate with a contoured, reflective surface. The first layer may substantially maintain the same optical properties as the substrate without the first layer. The first layer may be substantially conformal to the surface of the substrate and also may be a self assembled monolayer coating which may include at least a functional group that is hydrophobic.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/388,372, filed Sep. 30, 2010, entitled “Cleanable protectivecoating for projection screens,” the entirety of which is hereinincorporated by reference.

TECHNICAL FIELD

This disclosure generally relates to coatings for screens, and morespecifically relates to protective coatings for projection screens thatare designed to preserve polarization for stereoscopic projectionenvironments.

BACKGROUND

Cinema auditoriums are notoriously dirty and typically expose theprojection screen to a large variety of contaminants that can negativelydegrade the performance of the projection screen. A casual inspection ofscreens that have been installed for any significant length of time suchas, greater than about a year, yields a surprising array ofcontaminants. In addition to the accumulation of dust, which in somecases may be significant, contaminants may include beverages such assoda, juice, tea, coffee, and so on, candy, oil residues which may befrom chips, popcorn and/or popcorn butter, nachos, and spit-wads.

Dust accumulation tends to be relatively uniform spatially, representinga gradual decay in overall performance, whereas the latter namedcontaminants are more localized, and can thus be visually distracting.It is often difficult to remove these contaminants without causing anoptical blemish through abrasive, mechanical, and/or chemical action. Incertain instances, the contaminant penetrates the projection screencoatings and/or substrate, causing a stain that cannot be cleanedthrough typical means. Similar environmental concerns that may providedirt and/or contaminants to the screens are also present in home,industrial, and professional environments.

BRIEF SUMMARY

According to the present disclosure, a method for providing a projectionscreen for receiving stereoscopic images may include providing asubstrate with a contoured, reflective surface, wherein light reflectedfrom the substrate substantially may undergo no more than a singlereflection and coating a first layer on the substrate with a contoured,reflective surface. The first layer may substantially maintain the sameoptical properties as the substrate without the first layer. Coating thefirst layer may decrease the surface energy of the substrate. Thesubstrate may substantially maintain the same polarization for incidentand reflected light, and the first layer may substantially maintain asimilar polarization of light as that of the incident and reflectedlight off of the substrate. The method may include increasing thecontact angle of a fluid that may be in contact with the first layer.The first layer may be substantially conformal to the contoured,reflective surface of the substrate and also may be a self assembledmonolayer coating which may be applied with a water-based spray process.The self assembled monolayer coating may molecularly bond to thecontoured reflective surface of the substrate. The self assembledmonolayer coating may include at least a functional group that ishydrophobic and the self assembled monolayer coating may be less thanapproximately 60 Angstroms after the self assembled monolayer coatingdries.

According to another aspect of the present disclosure, a projectionscreen for receiving stereoscopic images may include a substrate with acontoured, reflective surface, wherein light reflected from thesubstrate may substantially undergo no more than a single reflection.The projection screen may also include a first layer coated on thesubstrate with a contoured, reflective surface, wherein the first layermay substantially maintain the same optical properties as the substratewithout the first layer. The first layer may decrease the surface energyof the substrate.

Furthering the discussion of the projection screen, the substrate maysubstantially maintain the same polarization for incident and reflectedlight off of the substrate, and the first layer may also substantiallymaintain a similar polarization of reflected light off of the firstlayer as the polarization of the incident and reflected light off of thesubstrate. A contaminant may contact with the first layer and thecontact angle between the contaminant and the first layer may beincreased over a contact angle between the substrate and thecontaminant. The first layer may be substantially conformal to thecontoured, reflective surface of the substrate and may be a selfassembled monolayer coating which may also be applied with a water-basedspray process. The self assembled monolayer coating may include at leasta functional group that is hydrophobic and may be less thanapproximately 60 Angstroms after the self assembled monolayer coatingdries.

According to yet another aspect of the present disclosure, a method forproviding a cleanable projection screen may include providing asubstrate with a contoured, reflective surface, substantiallyeliminating double reflections of incoming light off of the contoured,reflective surface and coating a first layer on the substrate. The firstlayer may be a cleanable, protective layer that may substantiallymaintain the same optical properties of the substrate without the firstlayer.

These and other advantages and features of the present disclosure willbecome apparent to those of ordinary skill in the art upon reading thisdisclosure in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram illustrating a side view of a typicaltheatre, in accordance with the present disclosure;

FIG. 1B is a schematic diagram illustrating a top down view of a typicaltheatre, in accordance with the present disclosure;

FIG. 2A is a schematic diagram illustrating a profile of a section of anengineered surface, showing how incident light is typically reflected,in accordance with the present disclosure;

FIG. 2B is a schematic diagram illustrating a profile of a section of anengineered surface with a protective coating applied in an undesirablemanner such that incident light is undesirably reflected in a uniformdirection;

FIG. 3A is a schematic diagram illustrating a profile of a section of anengineered surface, showing how incident light is typically reflected,in accordance with the present disclosure;

FIG. 3B is a schematic diagram illustrating a profile of a section of anengineered surface with a protective coating applied in a manner suchthat incident light is reflected in a manner that does not preservepolarization;

FIG. 3C is a schematic diagram illustrating a profile of a section of anengineered surface with a protective coating applied in a manner suchthat incident light is reflected in a manner that preservespolarization; and

FIG. 4 is a schematic diagram illustrating a representation of a selfassembled monolayer structure on a substrate, in accordance with thepresent disclosure.

DETAILED DESCRIPTION

According to the present disclosure, a method for providing a projectionscreen for receiving stereoscopic images may include providing asubstrate with a contoured, reflective surface, wherein light reflectedfrom the substrate substantially may undergo no more than a singlereflection and coating a first layer on the substrate with a contoured,reflective surface. The first layer may substantially maintain the sameoptical properties as the substrate without the first layer. Coating thefirst layer may decrease the surface energy of the substrate. Thesubstrate may substantially maintain the same polarization for incidentand reflected light, and the first layer may substantially maintain asimilar polarization of light as that of the incident and reflectedlight off of the substrate. The method may include increasing thecontact angle of a fluid that may be in contact with the first layer.The first layer may be substantially conformal to the contoured,reflective surface of the substrate and also may be a self assembledmonolayer coating which may be applied with a water-based spray process.The self assembled monolayer coating may molecularly bond to thecontoured reflective surface of the substrate. The self assembledmonolayer coating may include at least a functional group that ishydrophobic and the self assembled monolayer coating may be less thanapproximately 60 Angstroms after the self assembled monolayer coatingdries.

According to another aspect of the present disclosure, a projectionscreen for receiving stereoscopic images may include a substrate with acontoured, reflective surface, wherein light reflected from thesubstrate may substantially undergo no more than a single reflection.The projection screen may also include a first layer coated on thesubstrate with a contoured, reflective surface, wherein the first layermay substantially maintain the same optical properties as the substratewithout the first layer. The first layer may decrease the surface energyof the substrate.

Furthering the discussion of the projection screen, the substrate maysubstantially maintain the same polarization for incident and reflectedlight off of the substrate, and the first layer may also substantiallymaintain a similar polarization of reflected light off of the firstlayer as the polarization of the incident and reflected light off of thesubstrate. A contaminant may contact with the first layer and thecontact angle between the contaminant and the first layer may beincreased over a contact angle between the substrate and thecontaminant. The first layer may be substantially conformal to thecontoured, reflective surface of the substrate and may be a selfassembled monolayer coating which may also be applied with a water-basedspray process. The self assembled monolayer coating may include at leasta functional group that is hydrophobic and may be less thanapproximately 60 Angstroms after the self assembled monolayer coatingdries.

According to yet another aspect of the present disclosure, a method forproviding a cleanable projection screen may include providing asubstrate with a contoured, reflective surface, substantiallyeliminating double reflections of incoming light off of the contoured,reflective surface and coating a first layer on the substrate. The firstlayer may be a cleanable, protective layer that may substantiallymaintain the same optical properties of the substrate without the firstlayer.

Traditional unity gain or Lambertian-like screens used in twodimensional (2D) presentations do not utilize engineered surfaces forthe control of light dispersion. The scatter characteristics andvisually pleasing matte appearance of such screens are the result ofhomogenization from multiple random scattering events from very smallfeatures, for example, less than approximately 20 microns, on the screensurface and within the bulk of the material. Accumulated dust typicallyhas low density and extremely high surface area and so to a goodapproximation, the effect of dust is that of an additional lambertiandiffuser. Therefore, apart from a slight loss of approximately zero toten percent in light reflection efficiency, which may be due toabsorption of light by the dust, the accumulation of dust on such screensurfaces has relatively little impact on scattering characteristics.

Alternatively, other screens may have engineered surfaces designed tosubstantially control light dispersion. More specifically, surfaces maybe designed to substantially preserve the state of polarization (SOP),and may also be somewhat intolerant of dust accumulation. For highquality passive polarized 3D projection, the depolarization in thecenter of the screen may be less than approximately 1.5%. Further,accumulated dust may scatter approximately 3% of the total light, thusadding an additional approximately 1.5% depolarization to the nativecontribution of the screen. Of note, the relative contribution of thedust may depend upon viewing angle unless the distribution profile ofthe screen is also lambertian. The surface of the screen can be asophisticated optical component, and in some cases, engineered tonanometer-scale dimensions for optimum optical performance.

Additionally, once the screens with engineered surfaces are exposed tocontaminants, the performance of these screens may be negativelyaffected. Image brightness for 2D projection may undergo a loss in lightintensity of approximately 3%, which may be completely negligible.However, for 3D projection, the approximately 3% loss contributesapproximately 1.5% to the depolarization. For 3d projection, this amountof loss in light intensity may provide subpar viewing conditions.

FIG. 1A is a schematic diagram illustrating a side view of a typicaltheatre and FIG. 1B is a schematic diagram illustrating a top down viewof the typical theatre. In FIG. 1A, movie theatre 100 includes areflective screen 110, a projector platform 120, and a viewing area 130.Projector platform 120 may include projector 121 and polarization switch122. Viewing area 130 may provide seats organized in rows away from thescreen, defining a viewing area or viewing for viewers that may sit (orstand) in different places within the viewing area 130. For instance, afirst viewer may be located at the front-left viewing position 132 ofthe movie theatre 100, and receive reflected light 142. A second viewermay be located at the rear-left viewing position 134 and receivereflected light 144. A third viewer may be located in a central viewingposition 136 as shown in FIG. 1B.

Three dimensional projection systems may project three dimensionalcontent which may be decoded with the appropriate matched eyewear.Stated differently, three dimensional projection systems may projectleft and right eye images sequentially using orthogonal polarizations.Conventional reflective screens, including silver screens may reflectthe polarized light from the projector 120 to the moviegoer. Further, aspreviously discussed, the accumulation of dust on the screen surfaces ofconventional reflective screens may contribute to a loss in intensityand otherwise may not affect the scattering characteristics.

In the case of polarization preserving stereoscopic three dimensional(3D) screens, dust may produce random scatter that may negativelyinfluence the directionality of the screen as well as the state ofpolarization (SOP). Preserving polarization of reflected light from asurface may include employing relatively large, design contouredfeatures on the surface. For example, the features on the surface may beon the scale of a wavelength, and may be coated with reflective metals.Dispersive features of such surfaces may vary from approximately severalmicrons to over 100 microns. In an abrasive cleaning process, the peaksof such features may be vulnerable, with performance easily damaged.Examples of such engineered screens are provided in commonly-owned U.S.patent application Ser. No. 12/361,532, entitled “Polarizationpreserving front projection screen,” which is herein incorporated byreference in its entirety.

FIG. 2A is a schematic diagram illustrating a profile of a section of anengineered surface, showing how incident light may be typicallyreflected. As shown in FIG. 2A, the engineered surface 200 may includeat least contoured features 210 and 215. Although only two contouredfeatures are shown in FIG. 2A, the screen surface may have significantlymore contoured features, such as thousands to millions of contouredfeatures across the screen surface. The number of contoured featuresillustrated in FIG. 2A is for discussion purposes only, and is not to beconsidered limiting.

Additionally in FIG. 2A, incoming ray 220 a may undergo a singlereflection to produce reflected ray 220 b. The contoured features 210and 215 may be located on the screen such that most to all of theincoming light may substantially undergo no more than one reflectionfrom the contoured surface. Further, all the contoured features (notshown in FIG. 2A) may be located on the screen surface such that anyincoming light may substantially undergo no more than one reflectionfrom the contoured surface. Stated differently, the screen surface maybe engineered such that double reflections of most to all of theincoming light may be substantially eliminated and most to all of theincoming light may substantially undergo no more than one reflection.Similarly and further to the discussion of FIG. 2A, incoming ray 230 amay undergo a single reflection to produce reflected ray 230 b andincoming ray 240 a also may undergo a single reflection to producereflected ray 240 b, and so on. Moreover, the contoured features 210 and215 may be located such that the distribution of scattered light isoptimized or primarily directed to the appropriate viewing area of thetheatre.

FIG. 2B is a schematic diagram illustrating a profile of a section of anengineered surface with a protective coating applied in an undesirablemanner such that incident light is undesirably reflected in a uniformdirection. As shown in FIG. 2B, the engineered surface 250 may includeat least contoured features 260 and 265. Similar to FIG. 2A, althoughonly two contoured features are shown in FIG. 2B, the screen surface mayhave significantly more contoured features, such as thousands tomillions of contoured features across the screen surface. The number ofcontoured features illustrated in FIG. 2B is for discussion purposesonly, and is not to be considered limiting.

Distinct from FIG. 2A, FIG. 2B includes a coating 270. As shown in FIG.2B, the coating 270 is primarily concentrated in the low area of theengineered surface in FIG. 2B. In one example, as the coating 270 dries,the free energy of the coating 270 may be minimized by minimizing theroughness of the free fluid surface. The free energy of the coating 270will be discussed in further detail herein. Because the coating 270 issomewhat planarized, the reflected light may be in a relatively moreuniform direction and the distribution of the scattered light of thecontoured surface may be significantly altered.

Additionally, in one example, it may be possible to encapsulate theengineered surface in a thick durable transparent overcoat with a mattesurface such as a dielectric to eliminate hot spots or areas with highreflectivity in the specular direction. However, in this example,burying the functional layer beneath a non-conformal random dielectricmay negatively affect both the diffusion and polarization preservationproperties of the screen. Partial and total internal reflection withinthe dielectric layer may produce additional, undesirable reflectionsthat may modify the gain profile and may also degrade the polarization.In the case that polarization of the reflected light is degraded or notmaintained, the left and right eye images may be visible to the oppositeeye. Stated differently, when the polarization of reflected light is notmaintained, the left eye images may be visible in the right eye and theright eye images may be visible in the left eye.

The present disclosure provides a coating which, while substantiallymaintaining the optical properties of the surface, may decrease thesurface energy such that contaminants either substantially fail to bondto the surface or bond weakly. The surface energy of the coating on thesurface and contaminants will be discussed in further detail herein.

FIG. 3A is a schematic diagram illustrating a profile of a section of anengineered surface, showing how incident light may be typicallyreflected. FIG. 3A is similar to FIG. 2A and includes the engineeredsurface 300 with at least the contoured features 310 and 315. Alsoillustrated in FIG. 3A is incoming ray 320 a and reflected ray 320 b.The incoming and reflected rays 320 a and 320 b respectively, mayillustrate a single reflection off of the engineered surface 300.Furthermore, reflected ray 320 b may illustrate that the distribution ofthe scatter profile may be greater than if the reflected ray 320 b wereto reflect off of a substantially planarized surface such as illustratedby the coating 270 of FIG. 2B.

FIG. 3B is a schematic diagram illustrating a profile of a section of anengineered surface with a protective coating applied in a manner suchthat incident light is reflected in a manner that does not preservepolarization. Similar to FIG. 2B, FIG. 3B illustrates an engineeredsurface 350 that may include at least two contoured features 360 and365. Similar to FIGS. 2A, 2B, and 3A, although only two contouredfeatures are shown in FIG. 3B, the screen surface may have asignificantly greater number of contoured features. Two contouredfeatures are illustrated in FIG. 3B for discussion purposes only andshould not be construed as a limitation of the disclosure.

FIG. 3B also illustrates a coating 370. Distinct from the coating 270 ofFIG. 2B, coating 370 of FIG. 3B may be substantially conformal and maynot accumulate in the low area between the contoured features 360 and365. Even though the coating 370 may conform to the engineered surface350, the thickness of coating 370 may be such that undesirable partialreflection of light and refraction may occur within the coating. Asshown in FIG. 3B, incoming ray 380 a may produce reflected ray 380 b.However, incoming ray 380 a may also produce refracted ray 382 a andinternally reflected rays 382 b and 382 c. Internally reflected ray 382b may produce ray 384 which may reflect off of contoured feature 365 toproduce reflected ray 386. Continuing the discussion of FIG. 3B, ray 384may also produce refracted ray 382 within the coating 370.

The partial reflection of light and refraction illustrated in FIG. 3Bmay modify the gain properties of the screen without the coating 370,thus the coating 370 may fail to substantially maintain the opticalproperties of the engineered surface 350, and accordingly, the screen.Of note, for polarization preserving screens, the thickness of coating370 may cause an increase in the number of undesirable multiplereflection events that a single ray may experience which may be aprimary source of depolarization of polarized light. Conformal coatingsthat are approximately one half of a wavelength in thickness may improvethe reflectivity in the approximate range of 75-80% for bare aluminum toover approximately 90% in the visible region of the spectrum, but suchthicknesses, generally do not significantly enhance the durabilityagainst the abrasive cleaning action.

FIG. 3C is a schematic diagram illustrating a profile of a section of anengineered surface with a protective coating applied in a manner suchthat incident light is reflected in a manner that preservespolarization. Similar to FIG. 3B, FIG. 3C includes a coating 376. Asillustrated, the coating 376 of FIG. 3C is substantially conformal andmay not substantially accumulate in the low area between the contouredfeatures 377 and 378. Further, FIG. 3C illustrates a sufficiently thincoating 376 which may be such that desirable reflection of light mayoccur in that the polarization of the incoming may be substantiallypreserved when reflected.

Further in FIG. 3C, coating 376 is sufficiently thin so that refractionand internal reflections may not occur due to the coating 376 or in thecase they do occur, they may be negligible. In FIG. 3C incoming ray 381a reflects and produces reflected ray 381 b. The reflected ray 381 b mayreflect in a similar manner as a ray that may reflect off of thesubstrate without the coating 376. Likewise, incoming ray 382 a reflectsoff of the coating 376 and produces reflected ray 382 b, in a similarmanner as a ray that may reflect off of the substrate without thecoating 376.

One embodiment of a conformal coating is a Self Assembled Monolayer(SAM) coating that may molecularly bond to the engineered surface. A SAMis an organized layer of amphiphilic molecules in which one end of themolecule, the “head group” shows a special affinity for a substrate.SAMs also typically have a tail with a functional group at the terminalend as seen in FIG. 4. FIG. 4 is a schematic diagram illustrating arepresentation of a self assembled monolayer structure on a substrate.In FIG. 4, the head group 410 is depicted as bonded to the substrate405. The substrate 405 may include an engineered surface (not shown),and the head group 410 may bond to the engineered surface as well. Alsoas shown in FIG. 4, the SAM coating may include a tail 420, and afunctional group 430. In one example, the functional group 430 may behydrophobic.

The SAM coatings may lower the contact angle of the surface as measuredby water or oil contact angles. For example, the water contact angle ofan aluminum surface may increase from less than approximately 60° togreater than approximately 100°. Because of the chemical bond betweenthe SAM coating and the substrate, the coating may exhibit at least someresistance to light abrasion that may occur when cleaning and may remainsubstantially chemically unaffected by typical cleaning solvents. Thethickness of such monolayers may be significantly smaller than thewavelength of visible light, for example less than approximately 50 nm,and so the impact on the surface reflectivity may be extremely small ornegligible.

Another embodiment of a screen coating may be conformal to theunderlying surface. This may minimize the impact on the distribution ofscattered light of the additional optical surface such thatdepolarization may remain less than approximately 1.5% within the centerof the screen or such that the change in gain may be less thanapproximately 10%. However, unless the conformal coating is also verythin, for example, less than approximately 0.5 microns, there may be animpact to the distribution of scatter light and polarization primarilydue to internal reflections within the coating.

Returning to the discussion of FIG. 3B, thick conformal coatings, suchas coating 370, may allow partial reflection of light and refractionwithin the coating. The partial reflection and refraction within thecoating may modify the designed gain properties of the screen. Also aspreviously discussed, for polarization preserving screens, the thickcoating may increase the number of undesirable multiple reflectionevents that a single ray may experience which may be a primary source ofdepolarization. Conformal coatings that may be a fraction of awavelength in thickness can actually improve the reflectivity over abroad range of the spectrum, but such thicknesses do not significantlyenhance the durability against the abrasive cleaning action. Finally,for polarization preserving screens, it may be desirable for thetransparent optical coating to have extremely low birefringence suchthat the retardance within the layer is less than approximately 5 nm.

General approaches for cleaning the surface of the screen may includemanufacturing the screen such that the surface may be substantiallyunaffected by an amount of abrasion sufficient to substantially cleanany contaminant, and/or may also include the identification of acleaning prescription that may substantially remove contaminantssubstantially without undue abrasion. The first solution may becomplicated by both the optical nature of the screen and the need to notmodify it to affect its optical designed performance characteristics, aswell as the flexible nature of the screen surface. Due to the widevariety of contaminants possible, the second solution has limitedusefulness.

A cinema projection screen may uniformly scatter reflected light intothe viewing area while avoiding sending any substantial reflections inany one direction. Should substantial reflections occur in approximatelythe same direction, the result may be a hotspot. For example, a smoothtransparent coating on a diffusing substrate may produce an undesirable,sharp approximately four percent spike in reflectivity in the speculardirection. In practice this may indicate that the surface should besufficiently rough on a microscopic scale such that there may be no welldefined reflection direction. This desired roughness may be the mainsource of difficulty in cleaning the screen surface. The relatively highsurface area may improve the adhesion of contaminants. Additionally, themicro/meso-scopic pits and valleys in the surface may protect somecontaminants from abrasive cleaning Abrasive action applied to thescreen surface may impart more force and thus more damage to the peaksof the rough surface. Therefore, inadvertent modification to thedistribution of light scattered from the screen may occur.

Should the surface have a relatively high free energy, then fluidcontaminants may tend to wet the surface. At the same time, the freeenergy of the fluid is minimized by minimizing the roughness of the freefluid surface. As the fluid dries, it will attempt to maintain thesmooth free surface by concentrating in the low areas as shown in FIG.2B. Except for extremely macroscopically rough surfaces or thin initialfluid applications, the result may be a substantially planarized surfacewith increased hotspots and in which the filled valleys tend to reflectincident light in a substantially uniform direction.

By decreasing the surface energy of the screen, it may be possible toincrease the contact angle of many contaminating fluids. Because of thevertical orientation of the screen, this may allow many contaminants tosimply de-wet and then “roll” off the surface. Any contaminants that doadhere to the surface may bond with lower energy. Therefore the cleaningprocess necessary to remove such stains can be significantly lessaggressive.

In some cases it is possible to loosen the adhesion of a stain bysoaking the surface in a mild solvent. However, in a cinema environmentit is difficult to apply a fluid solvent to the vertically installedsurface for sufficient durations. Furthermore, in the case of aluminumcoated diffusers, the thin aluminum coating is especially vulnerable toreaction with water or other solvents.

There are various oxide coatings such as, but not limited to, MgF2,SiO2, and so on, that may be available that can substantially increasethe abrasion resistance of a surface. For example, a cleaning method maybe employed on a surface and may damage the surface such that the damagemay be reasonably visible to a viewer. Continuing the example, a coatingmay be deposited on the surface and the same cleaning method may damagethe surface less than a just noticeable difference. Even so, it may beimpractical to apply such evaporative coatings to the large area of acinema screen after it has been seamed and/or sprayed with silver paint.The hard nature of these coatings also makes them brittle and thereforeprone to cracking on the flexible surface of the roll stock prior toseaming.

Aluminum coated first-surface diffusers as described in U.S. Pat. Pub.No. 2009/0190210, which is herein incorporated by reference in itsentirety, may prove to be an especially difficult case to clean. Due tothe relatively small size of the features which may be employed for sucha structure, the bare aluminum and any native oxide that grows on it mayhave insufficient durability to most sources of abrasion. The dominantfailure mechanism may be removal of the evaporated/sputtered aluminumfilm. Further, due to the brittle nature of the oxide, insufficientsupport of the surface by the polymer substrate may lead to cracking ofthe film. If the adhesion of the aluminum is stronger than the adhesionof the aluminum to the substrate then the aluminum can be completelyremoved. Otherwise only the oxide may be removed which may allow thealuminum to be further damaged by subsequent abrasion or by oxidation.

Recognizing the difficulties with abrasively cleaning a cinema screen orcleaning it by means of a solvent, it is desirable to prevent orminimize adhesion of stains. This can be accomplished by decreasing thesurface energy of the screen surface. The change in surface energy maybe directly observable as an increase in the water-contact angle togreater than approximately 80 degrees and in some cases greater thanapproximately 110 degrees. This de-wetting of water is referred to ashydrophobicity.

In the case of conventional cinema screens, the protective coatingshould ideally be compatible with air-spray application and should notrequire heating of the substrate in order to cure the coating.

Recently, a new class of hydrophobic SAM (self-assembling monolayer)coatings has become available which has several desirable properties.Currently these films manufactured by companies such as Aculon, locatedin San Diego, Calif., may be used for protecting eyeglasses, displays,jewelry, stainless steel, and as mold release agents.

In another embodiment a SAM coating can be used to modify the mechanicalproperties of a screen surface to enable cleaning, with little to zeroimpact on the optical properties. SAM coatings may also be compatiblewith screen manufacturing processes, as they may be applied in awater-based spray process. The SAM coating can be applied as a finalcoat, in a conventional screen manufacturing process, or can be appliedusing any number of wet coating processes for manufacturing screenmaterials that are seamed after coating, including such screen materialsas UV embossed and metalized surfaces. A SAM coating in accordance withthe present disclosure, may be applied in two or more applications toinsure coverage, with a dried thickness of less than approximately 60Angstroms. It may be applied directly to the reflective coating or to athin conformal dielectric overcoat, which may be employed to, forexample, substantially eliminate the growth of native oxide.

As may be used herein, the terms “substantially” and “approximately”provide an industry-accepted tolerance for its corresponding term and/orrelativity between items. Such an industry-accepted tolerance rangesfrom less than one percent to ten percent and corresponds to, but is notlimited to, component values, angles, et cetera. Such relativity betweenitems ranges between less than one percent to ten percent.

While various embodiments in accordance with the principles disclosedherein have been described above, it should be understood that they havebeen presented by way of example only, and not limitation. Thus, thebreadth and scope of the embodiment(s) should not be limited by any ofthe above-described exemplary embodiments, but should be defined only inaccordance with any claims and their equivalents issuing from thisdisclosure. Furthermore, the above advantages and features are providedin described embodiments, but shall not limit the application of suchissued claims to processes and structures accomplishing any or all ofthe above advantages.

Additionally, the section headings herein are provided for consistencywith the suggestions under 37 CFR 1.77 or otherwise to provideorganizational cues. These headings shall not limit or characterize theembodiment(s) set out in any claims that may issue from this disclosure.Specifically and by way of example, although the headings refer to a“Technical Field,” the claims should not be limited by the languagechosen under this heading to describe the so-called field. Further, adescription of a technology in the “Background” is not to be construedas an admission that certain technology is prior art to anyembodiment(s) in this disclosure. Neither is the “Summary” to beconsidered as a characterization of the embodiment(s) set forth inissued claims. Furthermore, any reference in this disclosure to“invention” in the singular should not be used to argue that there isonly a single point of novelty in this disclosure. Multiple embodimentsmay be set forth according to the limitations of the multiple claimsissuing from this disclosure, and such claims accordingly define theembodiment(s), and their equivalents, that are protected thereby. In allinstances, the scope of such claims shall be considered on their ownmerits in light of this disclosure, but should not be constrained by theheadings set forth herein.

1. A method for providing a projection screen for receiving stereoscopicimages, comprising: providing a substrate with a contoured, reflectivesurface, wherein light reflected from the substrate substantiallyundergoes no more than a single reflection; and coating a first layer onthe substrate with a contoured, reflective surface, wherein the firstlayer substantially maintains the same optical properties as thesubstrate without the first layer.
 2. The method of providing aprojection screen of claim 1, wherein coating the first layer furthercomprises decreasing the surface energy of the substrate with acontoured, reflective surface.
 3. The method of providing a projectionscreen of claim 1, wherein the substrate substantially maintains thesame polarization for incident and reflected light, further wherein thefirst layer substantially maintains a similar polarization of light. 4.The method of providing a projection screen of claim 1, furthercomprising increasing the contact angle of a fluid, wherein the fluid isin contact with the first layer.
 5. The method of providing a projectionscreen of claim 1, wherein the first layer is substantially conformal tothe contoured, reflective surface of the substrate.
 6. The method ofproviding a projection screen of claim 1, wherein the first layer is aself assembled monolayer coating.
 7. The method of providing aprojection screen of claim 6, wherein the self assembled monolayercoating molecularly bonds to the contoured reflective surface of thesubstrate.
 8. The method of providing a projection screen of claim 1,wherein coating the first layer further comprises applying the firstlayer with a water-based spray process.
 9. The method of providing aprojection screen of claim 6, wherein the self assembled monolayercoating includes at least a functional group that is hydrophobic. 10.The method of providing a projection screen of claim 6, wherein the selfassembled monolayer coating is less than approximately 60 Angstromsafter the self assembled monolayer coating is dry.
 11. A projectionscreen for receiving stereoscopic images, comprising: a substrate with acontoured, reflective surface, wherein light reflected from thesubstrate substantially undergoes no more than a single reflection; anda first layer coated on the substrate with a contoured, reflectivesurface, wherein the first layer substantially maintains the opticalproperties as the substrate without the first layer.
 12. The projectionscreen of claim 11, wherein coating the first layer further comprisesdecreasing the surface energy of the substrate.
 13. The projectionscreen of claim 11, wherein the substrate substantially maintains thesame polarization for incident and reflected light off of the substrate,further wherein the first layer substantially maintains a similarpolarization of reflected light off of the first layer.
 14. Theprojection screen of claim 11, wherein a contaminant is in contact withthe first layer, further wherein the contact angle between thecontaminant and the first layer is increased.
 15. The projection screenof claim 11, wherein the first layer is substantially conformal to thecontoured, reflective surface of the substrate.
 16. The projectionscreen of claim 11, wherein the first layer further comprises a selfassembled monolayer coating.
 17. The method of providing a projectionscreen of claim 11, wherein coating the first layer further comprisesapplying the first coating with a water-based spray process.
 18. Themethod of providing a projection screen of claim 16, wherein the selfassembled monolayer coating includes at least a functional group that ishydrophobic.
 19. The method of providing a projection screen of claim 6,wherein the self assembled monolayer coating is less than approximately60 Angstroms after the self assembled monolayer coating is dry.
 20. Amethod for providing a cleanable projection screen, comprising:providing a substrate with a contoured, reflective surface;substantially eliminating double reflections of incoming light off ofthe contoured, reflective surface; and coating a first layer on thesubstrate with a contoured, reflective surface, wherein the first layeris a cleanable, protective layer that substantially maintains the sameoptical properties of the substrate without the first layer.